Variations of Electron Fluxes in the Outer Radiation Belt: Influence of High-Latitude Traps in the Dayside Cusps

Abstract

Bifurcation of the drift trajectory of an energetic particle, which occurs near the daytime magnetopause, transfers it from the equatorial region to high-latitude zones located in the vicinity of the dayside magnetospheric cusps. With strong rearrangements of the magnetospheric field occurring during a magnetic storm, the approach of the drift trajectory to the dayside magnetopause, leading to the loss of particles from the belt (“dropout”) upon crossing it, also gives rise to the simultaneous exit of the near-equatorial drift trajectory into the bifurcation zone. The processes of violation of adiabatic invariants occurring in this case should lead to the exchange of particles between high-latitude traps and the near-equatorial trapping zone. These effects should be taken into account in further modeling of variations in the outer radiation belt in the course of a magnetic storm, carried out in relation to individual storms.